This invention relates to a device for positioning material to be printed for use in a printing apparatus in which printing is applied to material made of metal sheet material such as aluminum plate and tin plate.
In the conventional printing apparatus shown in FIG. 10, a stopper (gripper face) 61 is provided in a specified position on a circumferential surface of an impression cylinder 60. A leading end of material 26 to be printed (hereinafter referred to as printing material 26) in contact with the stopper 61 is pressed and held against a positioning plate 62 by an unillustrated holding claw. In this way, the printing material 26 is positioned with respect to a specified image area defined on a surface of an unillustrated blanket cylinder, so that the image on the blanket cylinder is transferred to the printing material 26 at a proper position. The stopper 61 is formed at a leading end of a lower member 67 supported slidably on a leading end portion of a pivotal arm 64 pivotally supported to a support shaft 63. The lower member 67 is disposed below an upper member 66 secured to the pivotal arm 64 with a mounting bolt 65. To the upper member 66 is rotatably mounted an eccentric pin 68. When the eccentric pin 68 is rotated with the mounting bolt 65 unfastened, the lower member 67 moves forward and backward in a direction of transport of the printing material 26, whereby the position of the stopper 61 is minutely adjusted.
With the positioning device thus constructed, when the position of the stopper 61 is to be minutely adjusted, it is necessary that the printing apparatus is stopped, and the eccentric pin 68 is manually rotated to move the lower member 67 forward and backward. The printing apparatus is started again after the minute adjustment is made, and a printed state of the printing material is checked during a printing operation. Accordingly, it has been the problem that the printing operation is repeatedly started and stopped to perform adjustment of the stopper 61 until displacement of images superimposed on the printing material is completely corrected.
It is an object of the present invention to overcome the foregoing problem and to provide a device for positioning printing material for use in a printing apparatus which can adjust a position of a stopper rapidly and accurately.